According to the datasheet it has a PWN frequency of about 1kHz (= 1000 cycles per second). So it would be simple to measure its duty cycle with any MCU.
For example you could use a separate Arduino device and create a simple sketch that measures the ‘ON’ time in microseconds. Since the minimal dim level is 1% and maximum is 100%, you will measure an ON time between ~0.01 ms = dimmed and ~1 ms = full brightness.
The datasheet does not specify if the PWM signal briefly goes low between cycles. If not, you would need a timer to stop measuring. Or you could program the device to set a maximum dim level of 99%.
BTW, The Pi is also capable of reading the PWM signal (but not at 24V). Since this device is handling multiple things, an interrupt and timer driven approach would be needed. And whether that can be accomplished in a simple language like Python, without missing cycles, is uncertain. Programming in for instance C/C++ would also be an option, but that is more complex (e.g. no cross compiler for Windows).
However, I wonder what exactly you want to accomplish. Your initial request was about reading the dim level, but now
you mention that you want to set the dim level from OH. That’s more or less the oposite of measuring it…
On a side note: I’m wondering why you want to use these expensive devices for something as simple as control a few LEDs from OH?